Rational treatment options for T1/2N0M0 squamous cell carcinoma of the anal canal: a population-based study combined with external validation.

BACKGROUND

Treatment options for T1/2N0M0 anal squamous cell carcinoma include chemotherapy, radiotherapy, chemoradiotherapy, and local excision, although the optimal treatment method has not been determined.

METHODS

The National Cancer Institute Surveillance, Epidemiology and Results database was used to search and screen 1465 patients with cT1/2N0M0 anal squamous cell carcinoma who were clinically diagnosed between 2004 and 2016. Survival analysis was performed using the Kaplan-Meier method and log-rank test. Cox proportional hazards regression analysis was performed to screen independent prognostic factors and build a nomogram survival prediction model. According to the risk score, patients were divided into low, medium, and high risk groups using X-tile software.

RESULTS

Age, sex, grade and cT stage were identified as independent prognostic factors for cT1/2N0M0 anal squamous cell carcinoma and were included in the nomogram to construct a prediction model. The C-index of the model was 0.770 [95% confidence interval (CI), 0.693-0.856], which was higher than the C-index of T stage 0.565 (95% CI, 0.550-0.612). Low-risk patients benefited from local resection, moderate-risk patients benefited from radiotherapy, and high-risk patients benefited from radiotherapy or chemoradiotherapy. This was confirmed using external validation data from the center.

CONCLUSION

The nomogram developed in this study effectively and comprehensively evaluated the prognosis of patients with cT1/2N0M0 squamous cell carcinoma of the anal canal. Local excision is recommended for low risk patients, radiotherapy for moderate-risk patients, and radiotherapy or chemoradiotherapy for high-risk patients.